To compare between groups, and correlate within subjects, the changes in 49 hour lumbar CSF levels of indoleamines and changes in mood behaviors with a depletion of plasma tryptophan (TRP, the precursor of serotonin, 5HT) in twelve bipolar depressed patients. Within subject comparisons are planned between a baseline TRP depleted state prior to treatment and a TRP depleted state during antidepressant line treatment. Additional comparisons will be analyzed between previously studied normals and other psychopathologic groups. This will compare sertraline and bupropion effects on central indoleamine metabolism and mood. CSF levels of the antidepressants at steady state will be compared to plasma levels. CSF levels of indoleamines at baseline will correlate with mood improvement after treatment. The primary objectives will generalize to other indoleamines. Shifts in ratios between CSF levels of various indoleamines during different phases of TRP depletion will provide information regarding chronic effects of sertraline on indoleamine metabolism.